Had a 12 bolt c clip rear laying around the shop and decided to put it in my 71 442. Put new lower arms on it while rear was out. My question is the originals are both Identical. The reproductions are definitely a left and a right. Bought these from parts place(mistake)
years ago and didnt notice a difference until I was doing the install. Called them and they said there is definitely a left and right. They didn't know which one went where.. Anyone ever hear of this with reproduction arms?
Thanks

 

There is no difference from left to right as far as I know. There is a front and a back based on the sway bar holes.

 

The two holes for the sway bar go towards the rear. Other than that, if the bushings are tight in the arms then it doesn't matter which is which.

 

I bought the boxed TPP arms 10 years ago pretty much like joes pic no leftor right just 2 identical stamped pieces.

 

This is another one of those topics that seems to generate a disproportionate number on this forum. The bottom line is that this isn't rocket science. The LCAs are just two identical rubber bushings connected by a steel channel. The suspension only cares that the distance between the bushings remains constant - the rest is irrelevant. Except for the sway bar mounting holes, you could swap them end-for-end and the car wouldn't know the difference. If there were clearance at the mounting ears on the rear axle, you could even flip them upside down and the suspension would still work. My point about the bushings being mounted securely is that the OEM bushings have two different diameters where they fit into the arms. The diameter at the end with the flange is slightly larger than the diameter at the other end so that they slip easily into the arms until the final fraction of an inch. Note the slightly larger diameter at the flange end of these bushings.



Every single arm I've ever seen has been stamped exactly the same with the slightly larger diameter bushing hole on the passenger side of the arm. That means that the bushings must be inserted with the flange on that side of the arm. If someone installed them the other way (flange on the driver side) and the holes in the arm are sized for the OEM orientation, the bushings will not be retained properly. Take a close look at where the LCA stamping is formed around the hole. That short cylindrical area should be pointed towards the driver's side of the car. The bushing must be inserted from the OTHER side of the LCA. If the flange of the bushing is against this cylindrical area, it is not inserted properly and those arms should be returned. If the aftermarket LCAs really are RH/LH, then these cylindrical areas will be opposite each other - assuming the sway bar holes are in the same place.




Note by the way that this method of ensuring the bushings are inserted properly applies to ALMOST all of the GM stamped control arms (front and rear) where the bushing presses in two places but NOT 100% of them. I learned this when I tried to press the new front LCA bushings into the arms from my 67 Delta. You MUST pay close attention to the parts before you tear them apart, and READ the CSM, which points out differences like this.

 

Thanks guys for the replies. Because these are mirror images of each other the large end on the sway bar side can't face the same way as if it were OEM. If they face in the sway bar needs many shims on both sides. If they face out like in the pics the sway bar is tight with no shims. OEM had 3 shims. I guess I will go the no shim route. Hindsight would have redone the old arms. I see my next problem is the driveshaft is an inch shy going from 10 bolt type O to 12 bolt Ch**y.

 

Thanks Joe for the detailed response. We must have been posting at the same time. Like I said bought them years ago and didnt notice the bushing orientation. Came in separate boxes and 2 different part #. I will give it a closer look again and make sure I'm not missing something.

 

It looks like you have aftermarket arms with urethane bushings? I can't really comment on what some vendor did with their non-factory parts.

 

They are OEM replicas and are not urethane.....
supposedly

 

Then I have no idea why you would need that spacer. OEM bushings and arms do not.

 

Follow up. Read the top thread in the pic. There OEM
reproduction lower rear arms have a definite left and right. Live and learn. Hope this info helps someone else if you're looking for 100% OEM look.


Thanks to all.

 

Not sure if your point was to demonstrate that The Parts Place is full of it, which apparently they are, but the factory sway bar sits flush on the factory arms that are not RH/LH. The shims between the sway bar and the arms are only to take up manufacturing tolerances.

 

My point was just watch what you buy and who from claiming GM reproduction parts. Don't want the next guy to make the same mistake I did. Been out of the car hobby 25 + yrs and just getting back into it. There weren't any online parts suppliers back then. Just mail order from Fusiks and Year One if I remember correctly. Learned an expensive lesson that's all. Still may blast the old ones and rebush them and reinstall just because it bugs me.

 

Understood. Most of these vendors really don't have a clue. A perfect example is the plastic Chevelle cowl screen that they all sell for use on Oldsmobiles. Not.

 

Very old thread I know, but I just wanted add that I recently purchased a pair of rear lower control arms from Fusick for a 67 442. My old ones are exact duplicates of each other with identical bushing orientation like OP. The new ones are definitely left and right as the bushing orientation is flipped by design or mirrored if you will, as OP had mentioned. The new ones seem to be of good quality but do seem slightly lighter than the old ones but are boxed and have sway bar bolt holes so I will use them.
The reason I bought new was my old ones were hacked on by whomever was there before me. They cut into the "pressed fit" areas where bushings press in, I assume to make it easier to remove/install new ones. I tried installing new bushings in the old ones as is, but it was distorting badly under the pressure of pressing so I bailed and bought new.
All that being said there is no specific left or right in part numbers or online info so this was the first time I found anything relevant to my issue. Seems OP went with bushing case lip on inside for orientation, but from what I have read here it doesn't really matter so I will test fit and see if one way works better than the other. I do plan to try and repair the old ones with some weld and a bit of grinding to have some spares.

 

The OEM arms are the same on both sides. The only thing that matters is the center to center distance between the bushings. There was no reason to have different RH/LH stampings.

 

The relief cuts in those arms are the stuff of my nightmares.

Well done on replacing the arms entirely. When I added the Addco rear sway bars to my ‘66 big cars, I used reproduction boxed rear control arms from a ‘66 Cutlass after comparing measurements in the boneyard. Weird that they fit, but they’ve been on both of my big cars for decades with no issues.

Unlike the open factory rear trailing arms which I tried for a few years with the rear sway bar on the 98. The added stress without the boxed strength eventually caused a rear lower control arm to snap. On Christmas Eve one year.

Cheers
Chris